The invention relates generally to energy conservation structures and more specifically to an insulated vinyl window frame having insulated passageways disposed therein.
With the current emphasis on energy conservation, especially in the home, all aspects of construction components and methods have been carefully examined and oftentimes redesigned in an attempt to improve their energy conservation characteristics. With regard to windows and doors, such examination and redesign takes the form of the utilization of materials having high thermal resistance, the addition of insulating materials and the improvement of seal structures.
At one time, the window industry moved away from wood frames to aluminum frames for their ease of manufacture and assembly as well as lower cost. Unfortunately, the thermal conductivity of such frames creates a visible, undesirable side effect, namely, condensation on the interior surfaces during periods of cold weather. A less apparent though more economically significant difficulty of such frames is the energy loss through them due to their rather high thermal conductivity. U.S. Pat. Nos. 3,600,857 and 4,151,682 both address this difficulty. Both suggest the use of a thermal barrier or break of an insulating material between the inside and outside regions of the frame thereby interrupting what is otherwise rather significant thermal communication between the inside and the outside of a building, thereby reducing the condensation problem and the thermal losses attendant the significant thermal conduit provided by a metal structure extending from the inside heated space of a building to the outside.
Another construction approach which reduces the thermal conductivity of window and door frames is the utilization of plastic material such as vinyl to form portions of the frame. U.S. Pat. No. 4,286,716 teaches a composite frame having plastic inserts disposed in a metal support frame. Insulation is incorporated in the frame but the use of metal offsets the insulating effect of the insulation. This design, therefore, does not achieve the maximum possible insulating characteristics.
From the foregoing, it should be apparent that additional improvements directed to reducing the thermal conductivity of window and door frames are possible.